On 06/01/2012 12:38 AM, Igor Grinberg wrote: > On 05/31/12 19:50, Stephen Warren wrote: >> On 05/31/2012 04:13 AM, Marek Vasut wrote: >>> Dear Igor Grinberg, >>> >>>> On 05/30/12 19:45, Stephen Warren wrote: >>>>> From: Stephen Warren <[email protected]> >>>>> >>>>> Fix the .dts file USB unit addresses not to duplicate each-other. >>>>> >>>>> Fix the board name string to indicate the vendor is Compulab not NVIDIA. >>>>> >>>>> Signed-off-by: Stephen Warren <[email protected]> >>>> >>>> Acked-by: Igor Grinberg <[email protected]> >>> >>> Do we have one copy of the dts files here and one in Linux kernel tree? Are >>> they >>> the same? >> >> Both U-Boot and the kernel have their own copies of the .dts files. >> >> In general, the U-Boot copy would be identical to what's in the kernel, >> or a pure subset since mostly the kernel's driver support is more >> advanced, so we've added more nodes to the DT. >> >> That said, there are unfortunately some bizarre quirks in the way the >> U-Boot parses the device tree, such as requiring the /aliases node in >> order to enumerate at least some devices, the use of the Tegra clock >> binding that hasn't been incorporated into the kernel yet and is used >> for both clock and module reset functionality even though it's really >> only intended for clock functionality, and various other small >> properties that are U-Boot specific (although I forget if we managed to >> eliminate these all or not). These all end up causing differences >> between the two device tree files:-( > > Thanks for the information. > > I don't see any problem with having differences between the .dts files > in kernel and U-Boot, because the way I see it:
The issue isn't so much the duplicate files, but differing content. The whole point about DT is that it's a pure representation of the hardware; there should be no software-dependent design or data in it. Put another way, both U-Boot and the Linux kernel (and indeed anything else) should expect the DT to be written according to the same "bindings" design. This doesn't preclude the U-Boot DT file being a strict subset of the kernel file it it needs less information, but what is in both should match. > Also, IIRC, the intension was to remove the kernel .dts files after > "all bootloaders" know to boot the DT kernel... I don't believe it's anything to do with bootloaders. Bootloaders are already (in the main) expected to provide the DTB to the kernel as a separate entity, irrespective of whether the DTB is built by the kernel boot process or from some other repository. (Although there is CONFIG_APPENDED_DTB to support cases where this isn't possible, it's much preferred not to use this). Moving the .dts files out of the kernel is more purely about finding a place to put them I think. _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
